An air cleaner device for a vehicle, such as that disclosed in Japanese Accepted Patent Publication 2628641 (page 2, FIG. 3), is provided with a main air cleaner and a sub air cleaner.
For example, FIG. 6 of the present application is a plan view of a conventional air cleaner for a vehicle. The drawing shows an air cleaner device in which a sub air cleaner 203 is mounted on a carburetor 201 by way of an outlet tube 202 and a main air cleaner 205 is connected to the sub air cleaner 203 in the vehicle width direction using a connecting tube 204.
In the technique described in Japanese Accepted Patent Publication 2628641, the sub air cleaner 203 and the main air cleaner 205 are arranged in parallel in the vehicle-width direction of the vehicle and hence, for example, the sub air cleaner 203 and the main air cleaner 205 easily interfere with an occupant or are projected outwards, thus deteriorating the aesthetic appearance. In view of the above, it maybe desirable to reduce a projection amount of the air cleaner in the vehicle-width direction to prevent the interference of these cleaners with an occupant and to improve the aesthetic appearance. In this case, however, it is difficult to ensure capacities of the sub air cleaner 203 and the main air cleaner 205 and hence, particularly, with respect to a vehicle having an engine with a large stroke volume, it is difficult to achieve sufficient enhancement of output and the effective reduction of intake noises.